Sméagol (Trahald) was a Hobbit of Stoor-kind who lived on the banks of the Anduin in the later Third Age. He was an inquisitive Hobbit who was interested in roots and beginnings. His friend Déagol came upon the One Ring, but Sméagol murdered Déagol and took the Ring. He was eventually exiled by his people, and crept into the roots of the Misty Mountains, where he became the creature of the dark better known as Gollum.

Etymology

"Smials. A word peculiar to hobbits (not Common Speech), meaning 'burrow'; leave unchanged. It is a form that the Old English word smygel 'burrow' might have had, if it had survived. The same element appears in Gollum's real name, Sméagol."

― Tolkien

The name Smaug which means "squeezed through a hole" is also related.[1]